scholarly journals Supernovae and solar cycles embedded in a Dome F ice core

2009 ◽  
Vol 5 (H15) ◽  
pp. 630-631 ◽  
Author(s):  
Yuko Motizuki ◽  
Yoichi Naka ◽  
Kazuya Takahashi
Keyword(s):  
Depth Profile ◽  
Ice Core ◽  
Solar Cycles ◽  
Nitrate Ion ◽  
Ion Concentrations

AbstractWe have recently found signals of candidates for two historical supernovae and past solar cycles in a depth profile of nitrate ion concentrations in an ice core portion corresponding to the 10th and the 11th centuries. This ice core was drilled in 2001 at Dome Fuji (Dome F) station in Antarctica. We briefly review our findings and discuss why Dome F is appropriate for this study.

scholarly journals Constituent elements of insoluble and non-volatile particles during the Last Glacial Maximum exhibited in the Dome Fuji (Antarctica) ice core

2009 ◽  
Vol 55 (191) ◽  
pp. 552-562 ◽  
Author(s):  
Yoshinori Iizuka ◽  
Takayuki Miyake ◽  
Motohiro Hirabayashi ◽  
Toshitaka Suzuki ◽  
Sumito Matoba ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Calcium Ion ◽  
Ice Core ◽  
Ice Cores ◽  
Glacial Maximum ◽  
Ion Concentrations ◽  
Last Glacial ◽  
Insoluble Particles ◽  
Almost All ◽  
Constituent Elements

AbstractIn order to find environmental signals based on the dust and calcium-ion concentrations in ice cores, we determine the constituent elements of residue particles obtained after melting ice samples. We have designed a sublimating system that operates at −45°C, below the eutectic temperatures of major salts. This system permits us to obtain a great many non-volatile particles. After studying the non-volatile particles, we immersed them in water to remove soluble particles and compounds. We thereby analyzed a total of 1272 residue particles (from the melted sample), 2418 non-volatile particles (after sublimation) and 1463 insoluble particles taken from five sections of Last Glacial Maximum ice from the Dome Fuji (Antarctica) ice core. Their constituent elements were determined by scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) and compared to the dust, calcium-ion and sodium-ion concentrations measured by ion chromatography. Our results indicate that >99.9% of the insoluble particles contain silicon but no sulfur, nitrogen or chlorine. A significant number of the non-volatile particles, however, contain sulfur and chlorine. We conclude that insoluble dust consists mostly of silicate, that almost all calcium ions originate from calcium sulfate and that almost all sodium ions originate from sodium sulfate and sodium chloride.

A novel high-resolution laser-melting sampler for discrete analyses of ion concentrations and stable water isotopic compositions in firn and ice cores

2021 ◽  
Author(s):  
Yuko Motizuki ◽  
Yoichi Nakai ◽  
Kazuya Takahashi ◽  
Junya Hirose ◽  
Yu Vin Sahoo ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Depth Resolution ◽  
Climatic Changes ◽  
Accumulation Rates ◽  
Laser Melting ◽  
Ion Concentrations ◽  
Annual Layer ◽  
Annual Resolution ◽  
High Depth

<p>Ice cores preserve past climatic changes and, in some cases, astronomical signals. Here we present a newly developed automated ice-core sampler that employs laser melting. A hole in an ice core approximately 3 mm in diameter is melted and heated well below the boiling point by laser irradiation, and the meltwater is simultaneously siphoned by a 2 mm diameter movable evacuation nozzle that also holds the laser fiber. The advantage of sampling by laser melting is that molecular ion concentrations and stable water isotope compositions in ice cores can be measured at high depth resolution, which is advantageous for ice cores with low accumulation rates. This device takes highly discrete samples from ice cores, attaining depth resolution as small as ~3 mm with negligible cross contamination; the resolution can also be set at longer lengths suitable for validating longer-term profiles of various ionic and water isotopic constituents in ice cores. This technique allows the detailed reconstruction of past climatic changes at annual resolution and the investigation of transient ionic and isotopic signals within single annual layers in low-accumulation cores, potentially by annual layer counting.</p>

scholarly journals Response of regional climate and glacier ice proxies to El Niño-Southern Oscillation (ENSO) in the subtropical Andes

2008 ◽  
Vol 4 (1) ◽  
pp. 173-211
Author(s):  
E. Dietze ◽  
A. Kleber ◽  
M. Schwikowski
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Ice Core ◽  
La Niña ◽  
El Nino Southern Oscillation ◽  
Ion Concentrations ◽  
Major Ion ◽  
La Nina ◽  
Glacier Ice

Abstract. El Niño-Southern Oscillation (ENSO) is an important element of earth's ocean-climate system. To further understand its past variability, proxy records from climate archives need to be studied. Ice cores from high alpine glaciers may contain high resolution ENSO proxy information, given the glacier site is climatologically sensitive to ENSO. We investigated signals of ENSO in the climate of the subtropical Andes in the proximity of Cerro Tapado glacier (30°08' S, 69°55' W, 5550 m a.s.l.), where a 36 m long ice core was drilled in 1999 (Ginot, 2001). We used annual and semi-annual precipitation and temperature time series from regional meteorological stations and interpolated grids for correlation analyses with ENSO indices and ice core-derived proxies (net accumulation, stable isotope ratio δ18O, major ion concentrations). The total time period investigated here comprises 1900 to 2000, but varies with data sets. Only in the western, i.e. Mediterranean Andes precipitation is higher (lower) during El Niño (La Niña) events, especially at higher altitudes, due to the latitudinal shift of frontal activity during austral winters. However, the temperature response to ENSO is more stable in space and time, being higher (lower) during El Niño (La Niña) events in most of the subtropical Andes all year long. From a northwest to southeast teleconnection gradient, we suggest a regional water vapour feedback triggers temperature anomalies as a function of ENSO-related changes in regional pressure systems, Pacific sea surface temperature and tropical moisture input. Tapado glacier ice proxies are found to be predominantly connected to eastern Andean summer rain climate, which contradicts previous studies and the modern mean spatial boundary between subtropical summer and winter rain climate derived from the grid data. The only ice core proxy showing a response to ENSO is the major ion concentrations, via local temperature indicating reduced sublimation and mineral dust input during El Niño years.

scholarly journals Comparison of two ice-core chemical records recovered from the Qomolangma (Mount Everest) region, Himalaya

2002 ◽  
Vol 35 ◽  
pp. 266-272 ◽  
Author(s):  
Shugui Hou ◽  
Dahe Qin ◽  
Dongqi Zhang ◽  
Jiawen Ren ◽  
Shichang Kang ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Seasonal Variations ◽  
Monsoon Season ◽  
Ice Core ◽  
Far East ◽  
Mount Everest ◽  
Snow Layer ◽  
Ion Concentrations ◽  
The Mean

AbstractA 40.9 m ice core was recovered from Far East Rongbuk Glacier (FER), Qomolangma (Mount Everest), Himalaya, and an 80.4 m core from neighboring East Rongbuk Glacier (ER). Both are dated by seasonal variations of δ18O and major-ionic profiles, together with references of β-activity peaks. In this paper we compare the chemical records of these two cores to show post-depositional modification processes. The smoothed β18O profiles of the two cores show a similar trend. However, the mean β18O value of the FER core for the period 1954—96 is 3.12%o less than that of the corresponding part of the ER core, and the major-ionic profiles of the two cores differ considerably. We suggest that melting-away of the snow layer deposited during the pre-monsoon season may account for lower β18O values of the FER than of the ER core, and higher terrestrial ion concentrations in the FER core for the period 1957-63 may contribute to changes by chemical reactions in the presence of snowmelting. The significantly decreased NH4 and, to a lesser degree, SO42 concentrations in the FER core could be caused by the ion elution process that moved most chemicals away with runoff.

scholarly journals Studies on microparticles contained in medium-depth ice cores retrieved from east Dronning Maud Land, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 73-79
Author(s):  
Akira Higashi ◽  
Yoshiyuki Fujii
Keyword(s):  
Elemental Composition ◽  
Depth Profile ◽  
Volcanic Ash ◽  
Ice Core ◽  
Compositional Analysis ◽  
Ice Cores ◽  
Cold Climates ◽  
Dronning Maud Land ◽  
Antarctic Research ◽  
South Sandwich Islands

SEM observations of microparticles in ice-core samples retrieved by the Japanese Antarctic Research Expedition in east Dronning Maud Land have been carried out since 1987. Morphology and elemental composition by EDS of many microparticles taken from various depths of the 700 m Mizuho ice core were compared with each other and with those of stratospheric microparticles in NASA Cosmic Dust Catalogs and microparticles hitherto found in deep ice cores retrieved in Antarctica. Number concentrations of microparticles were measured on all samples throughout the 700 m Mizuho ice core. Remarkable fluctuations found in the depth profile of the concentration seem to coincide with cold climates indicated by δ18O of the same core. Compositional analysis of volcanic ash at a depth of 500.7 m in the Mizuho ice core, dated at approximately 6000 years BP, indicates that the ash originated from the South Sandwich Islands.

scholarly journals Where is the 1-million-year-old ice at Dome A?

2018 ◽  
Vol 12 (5) ◽  
pp. 1651-1663 ◽  
Author(s):  
Liyun Zhao ◽  
John C. Moore ◽  
Bo Sun ◽  
Xueyuan Tang ◽  
Xiaoran Guo
Keyword(s):  
Heat Flux ◽  
Depth Profile ◽  
Ice Core ◽  
Three Dimensional ◽  
Melting Rate ◽  
Dome A ◽  
Geothermal Heat ◽  
Kunlun Station ◽  
Ice Fabrics ◽  
Basal Melting

Abstract. Ice fabric influences the rheology of ice, and hence the age–depth profile at ice core drilling sites. To investigate the age–depth profile to be expected of the ongoing deep ice coring at Kunlun station, Dome A, we use the depth-varying anisotropic fabric suggested by the recent polarimetric measurements around Dome A along with prescribed fabrics ranging from isotropic through girdle to single maximum in a three-dimensional, thermo-mechanically coupled full-Stokes model of a 70 × 70 km2 domain around Kunlun station. This model allows for the simulation of the near basal ice temperature and age, and ice flow around the location of the Chinese deep ice coring site. Ice fabrics and geothermal heat flux strongly affect the vertical advection and basal temperature which consequently control the age profile. Constraining modeled age–depth profiles with dated radar isochrones to 2∕3 ice depth, the surface vertical velocity, and also the spatial variability of a radar isochrones dated to 153.3 ka BP, limits the age of the deep ice at Kunlun to between 649 and 831 ka, a much smaller range than previously inferred. The simple interpretation of the polarimetric radar fabric data that we use produces best fits with a geothermal heat flux of 55 mW m−2. A heat flux of 50 mW m−2 is too low to fit the deeper radar layers, and 60 mW m−2 leads to unrealistic surface velocities. The modeled basal temperature at Kunlun reaches the pressure melting point with a basal melting rate of 2.2–2.7 mm a−1. Using the spatial distribution of basal temperatures and the best fit fabric suggests that within 400 m of Kunlun station, 1-million-year-old ice may be found 200 m above the bed, and that there are large regions where even older ice is well above the bedrock within 5–6 km of the Kunlun station.

scholarly journals CO2 diffusion in polar ice: observations from naturally formed CO2 spikes in the Siple Dome (Antarctica) ice core

2008 ◽  
Vol 54 (187) ◽  
pp. 685-695 ◽  
Author(s):  
Jinho Ahn ◽  
Melissa Headly ◽  
Martin Wahlen ◽  
Edward J. Brook ◽  
Paul A. Mayewski ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Diffusion Coefficient ◽  
Concentration Profile ◽  
Ice Core ◽  
Polar Ice ◽  
Common Assumption ◽  
Ion Concentrations ◽  
Co2 Diffusion ◽  
Siple Dome ◽  
Diffusion Rates

AbstractOne common assumption in interpreting ice-core CO2 records is that diffusion in the ice does not affect the concentration profile. However, this assumption remains untested because the extremely small CO2 diffusion coefficient in ice has not been accurately determined in the laboratory. In this study we take advantage of high levels of CO2 associated with refrozen layers in an ice core from Siple Dome, Antarctica, to study CO2 diffusion rates. We use noble gases (Xe/Ar and Kr/Ar), electrical conductivity and Ca2+ ion concentrations to show that substantial CO2 diffusion may occur in ice on timescales of thousands of years. We estimate the permeation coefficient for CO2 in ice is ∼4 × 10−21 mol m−1 s−1 Pa−1 at −23°C in the top 287 m (corresponding to 2.74 kyr). Smoothing of the CO2 record by diffusion at this depth/age is one or two orders of magnitude smaller than the smoothing in the firn. However, simulations for depths of ∼930–950 m (∼60–70 kyr) indicate that smoothing of the CO2 record by diffusion in deep ice is comparable to smoothing in the firn. Other types of diffusion (e.g. via liquid in ice grain boundaries or veins) may also be important but their influence has not been quantified.

scholarly journals Survey of Nitrate Ion Concentrations in Vegetables Cultivated in Plant Factories: Comparison with Open-Culture Vegetables

2017 ◽  
Vol 58 (1) ◽  
pp. 49-58
Author(s):  
Yuka OKA ◽  
Izumi HIRAYAMA ◽  
Mitsuhide YOSHIKAWA ◽  
Tomoko YOKOYAMA ◽  
Kenji IIDA ◽  
...  
Keyword(s):  
Nitrate Ion ◽  
Ion Concentrations
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